The present invention is based on a data processing method of processing data for transmission purposes and more particularly to such a method in which an input data stream is subjected to difference and convolutional coding after being subdivided into a plurality of data substreams of slower processing speed, and subsequently combined for transmission into at least two phase components.
In processing data subjected to difference coding and to convolutional coding, it is known to divide these data, particularly if high data rates are involved, into data substreams. In a TDRSS (Tracking and Data Relay Satellite System) system, the data substreams are individually convolutionally coded and are combined by means of multiplexers into interleaved output data streams which are then fed to a QPSK (Quadrature Phase Shift Keyed) modulator for transmission. At the receiving end, there then occurs the corresponding conversion. See for example, IEEE Global Telecommunications Conference, Globecom 83, San Diego, USA, Conference Record S, pages 1050-1053. For correct synchronization it is necessary to either have a fixed data transmission format or additional information must be transmitted, for example an added PN (pseudo-noise) sequence. Again, see the above Globecom 83 publication.